Population of coastal areas is the percent of the total population living within one hundred kilometres of the coastline. A country might also consider percentage of population in the low elevation coastal zone (<10 meters elevation) or percentage of population in river deltas. Please refer to http://www.un.org/esa/sustdev/natlinfo/ ... sheets.pdf

A coastal area is the part of the land affected by its proximity to the sea, and that part of the sea affected by its proximity to the land as the extent to which man's land-based activities have a measurable influence on water chemistry and marine ecology. (Please refer to European Environment Agency’s website at http://glossary.eea.europa.eu/ EEAGlossary /C/ coastal_ area.)